If an animal's blood oxygen level is normal, what color are its mucous membranes?

• A. Whitish
• B. Pink
• C. Dark red
• D. Bluish

Answer: (B)

Mucous membrane color reflects how well blood is being oxygenated and circulated. When blood is properly oxygenated, the hemoglobin is bright red, and this light red color shows through the thin mucous membranes, giving a pink appearance. A pink mucous membrane indicates normal oxygen delivery to tissues. If the membranes look bluish, that signals cyanosis from inadequate oxygen in the blood. Pale or white membranes suggest pallor from anemia or poor perfusion, and a much darker red isn’t typical of normal oxygenation. So, with normal blood oxygen, the mucous membranes are pink.